From 4e44e44b0bd25bc4ed23232f06fc7275f1e4e38d Mon Sep 17 00:00:00 2001 From: Mukesh Rathor Date: Tue, 31 Dec 2013 12:41:27 -0500 Subject: [PATCH] xen/pvh: MMU changes for PVH (v2) .. which are surprisingly small compared to the amount for PV code. PVH uses mostly native mmu ops, we leave the generic (native_*) for the majority and just overwrite the baremetal with the ones we need. At startup, we are running with pre-allocated page-tables courtesy of the tool-stack. But we still need to graft them in the Linux initial pagetables. However there is no need to unpin/pin and change them to R/O or R/W. Note that the xen_pagetable_init due to 7836fec9d0994cc9c9150c5a33f0eb0eb08a335a "xen/mmu/p2m: Refactor the xen_pagetable_init code." does not need any changes - we just need to make sure that xen_post_allocator_init does not alter the pvops from the default native one. Signed-off-by: Mukesh Rathor Signed-off-by: Konrad Rzeszutek Wilk Acked-by: Stefano Stabellini --- arch/x86/xen/mmu.c | 75 ++++++++++++++++++++++++++-------------------- 1 file changed, 43 insertions(+), 32 deletions(-) diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c index 9d74249542c5..490ddb354590 100644 --- a/arch/x86/xen/mmu.c +++ b/arch/x86/xen/mmu.c @@ -1757,6 +1757,10 @@ static void set_page_prot_flags(void *addr, pgprot_t prot, unsigned long flags) unsigned long pfn = __pa(addr) >> PAGE_SHIFT; pte_t pte = pfn_pte(pfn, prot); + /* For PVH no need to set R/O or R/W to pin them or unpin them. */ + if (xen_feature(XENFEAT_auto_translated_physmap)) + return; + if (HYPERVISOR_update_va_mapping((unsigned long)addr, pte, flags)) BUG(); } @@ -1867,6 +1871,7 @@ static void __init check_pt_base(unsigned long *pt_base, unsigned long *pt_end, * but that's enough to get __va working. We need to fill in the rest * of the physical mapping once some sort of allocator has been set * up. + * NOTE: for PVH, the page tables are native. */ void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn) { @@ -1888,17 +1893,18 @@ void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn) /* Zap identity mapping */ init_level4_pgt[0] = __pgd(0); - /* Pre-constructed entries are in pfn, so convert to mfn */ - /* L4[272] -> level3_ident_pgt - * L4[511] -> level3_kernel_pgt */ - convert_pfn_mfn(init_level4_pgt); - - /* L3_i[0] -> level2_ident_pgt */ - convert_pfn_mfn(level3_ident_pgt); - /* L3_k[510] -> level2_kernel_pgt - * L3_i[511] -> level2_fixmap_pgt */ - convert_pfn_mfn(level3_kernel_pgt); + if (!xen_feature(XENFEAT_auto_translated_physmap)) { + /* Pre-constructed entries are in pfn, so convert to mfn */ + /* L4[272] -> level3_ident_pgt + * L4[511] -> level3_kernel_pgt */ + convert_pfn_mfn(init_level4_pgt); + /* L3_i[0] -> level2_ident_pgt */ + convert_pfn_mfn(level3_ident_pgt); + /* L3_k[510] -> level2_kernel_pgt + * L3_i[511] -> level2_fixmap_pgt */ + convert_pfn_mfn(level3_kernel_pgt); + } /* We get [511][511] and have Xen's version of level2_kernel_pgt */ l3 = m2v(pgd[pgd_index(__START_KERNEL_map)].pgd); l2 = m2v(l3[pud_index(__START_KERNEL_map)].pud); @@ -1922,31 +1928,33 @@ void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn) copy_page(level2_fixmap_pgt, l2); /* Note that we don't do anything with level1_fixmap_pgt which * we don't need. */ + if (!xen_feature(XENFEAT_auto_translated_physmap)) { + /* Make pagetable pieces RO */ + set_page_prot(init_level4_pgt, PAGE_KERNEL_RO); + set_page_prot(level3_ident_pgt, PAGE_KERNEL_RO); + set_page_prot(level3_kernel_pgt, PAGE_KERNEL_RO); + set_page_prot(level3_user_vsyscall, PAGE_KERNEL_RO); + set_page_prot(level2_ident_pgt, PAGE_KERNEL_RO); + set_page_prot(level2_kernel_pgt, PAGE_KERNEL_RO); + set_page_prot(level2_fixmap_pgt, PAGE_KERNEL_RO); - /* Make pagetable pieces RO */ - set_page_prot(init_level4_pgt, PAGE_KERNEL_RO); - set_page_prot(level3_ident_pgt, PAGE_KERNEL_RO); - set_page_prot(level3_kernel_pgt, PAGE_KERNEL_RO); - set_page_prot(level3_user_vsyscall, PAGE_KERNEL_RO); - set_page_prot(level2_ident_pgt, PAGE_KERNEL_RO); - set_page_prot(level2_kernel_pgt, PAGE_KERNEL_RO); - set_page_prot(level2_fixmap_pgt, PAGE_KERNEL_RO); + /* Pin down new L4 */ + pin_pagetable_pfn(MMUEXT_PIN_L4_TABLE, + PFN_DOWN(__pa_symbol(init_level4_pgt))); - /* Pin down new L4 */ - pin_pagetable_pfn(MMUEXT_PIN_L4_TABLE, - PFN_DOWN(__pa_symbol(init_level4_pgt))); + /* Unpin Xen-provided one */ + pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd))); - /* Unpin Xen-provided one */ - pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd))); - - /* - * At this stage there can be no user pgd, and no page - * structure to attach it to, so make sure we just set kernel - * pgd. - */ - xen_mc_batch(); - __xen_write_cr3(true, __pa(init_level4_pgt)); - xen_mc_issue(PARAVIRT_LAZY_CPU); + /* + * At this stage there can be no user pgd, and no page + * structure to attach it to, so make sure we just set kernel + * pgd. + */ + xen_mc_batch(); + __xen_write_cr3(true, __pa(init_level4_pgt)); + xen_mc_issue(PARAVIRT_LAZY_CPU); + } else + native_write_cr3(__pa(init_level4_pgt)); /* We can't that easily rip out L3 and L2, as the Xen pagetables are * set out this way: [L4], [L1], [L2], [L3], [L1], [L1] ... for @@ -2107,6 +2115,9 @@ static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot) static void __init xen_post_allocator_init(void) { + if (xen_feature(XENFEAT_auto_translated_physmap)) + return; + pv_mmu_ops.set_pte = xen_set_pte; pv_mmu_ops.set_pmd = xen_set_pmd; pv_mmu_ops.set_pud = xen_set_pud;